The 16-mile bike trail along the George Washington Memorial Parkway and the Potomac River, from Memorial Bridge to Mount Vernon, is probably the most scenic bike trail in the East.

It is also, deservedly, the region's most crowded trail on weekends.

With panoramic vistas of Washington and its monuments, the bike trail passes through historic Old Town Alexandria, past marinas and over boardwalks through marshes and a bird sanctuary where bald eagles can occasionally be seen soaring above the river. For bicyclists, the shoreline looks much as it did when George Washington rode along it on his horse.

And this year the bike trail will have two added attractions.

The National Park Service is restoring some of the Spanish- American War gun batteries at Fort Hunt, and the U.S. Army Band, founded at Fort Hunt just after the turn of the century, will soon begin giving regular concerts there. The fort is beside the bike trail halfway between Alexandria and Mount Vernon

And on Daingerfield Island, just south of National Airport, a new $2.75-million marina restaurant -- with a bicycle shop attached -- has just opened beside the bike trail.

The Park Service will soon extend the Mount Vernon trail to Roosevelt Island, where construction is scheduled to start later this year on a new bicycle bridge that will connect to Rosslyn, Key Bridge and Arlington's I-66 bike trail. A side trail along Four Mile Run goes to Shirlington where it connects, awkwardly, with the W&OD Trail.

Parking lots at Daingerfield Island, Fort Hunt and Belle Haven picnic grounds, just south of Alexandria, are sometimes crowded. Many cyclists park their cars on Old Town streets and then pedal south or north.